The use of moist heating pads for therapeutic and dilating purposes have been written up in the literature. For example, U.S. Pat. No. 3,587,578 granted to Walker on Jun. 28, 1971 discloses a heat pack of laterally spaced cells that are fabricated with an inner layer of water pervious material and an outer layer of water impervious material which is molded to form spaced troughs. The material of the outer layer is a stretchable material and the inner layer is a non-stretchable material so as to be configured into a small diameter pack. This construction allows a larger area contact of the anatomy when compared with, for example, the construction of the heat pack described in the Jensen U.S. Pat. No. 2,710,008. The Jensen patent describes a heat pack that is fabricated from a two-sided tightly woven fabric stitched to form laterally spaced cells filled with a bentonite filler. Bentonite is characterized as an amorphous material that is capable of absorbing large volumes of water. Typically, these packs are dipped into hot water for a period of time to be allowed to heat up to the temperature of the boiling water, then removed and wrapped in a Turkish towel and ultimately applied to the desired anatomy of the patient being treated.
U.S. Pat. No. 5,178,139 granted to Angelillo et al on Jan. 12, 1993 discloses a heat pack and absorbent pad combination utilized for obstetrics and gynecology purposes that includes a chemical encased in a plastic bag internal of the pad that undergoes an exothermic reaction when mixed with a solvent to produce heat. An insulating pad is interposed between the plastic bag containing the chemical and the skin of the patient to provide a moderate thermal barrier between the two surfaces.
The pads disclosed in U.S. Pat. Nos. 3,587,578 and 2,710,008, supra, are reusable types and as discussed above require the heating by being immersed into hot water. The pad disclosed in U.S. Pat. No. 5,178,139, supra, is an absorbent pad and is not a heating pad in the same sense as the others inasmuch as the heat is thwarted so that only a minimal heat is allowed to flow toward the anatomy. One of the undesirable characteristics of the heating pads disclosed hereinabove is that it is necessary to preheat the pad by immersing it in hot water. This has a tendency of being initially hot and cooling down very quickly so that the heat varies over time during the course of application. Another disadvantage in the cellular construction is that the area where the adjacent cells are joined has a tendency of being cooler than the area directly under the cell.
My invention obviates the problems alluded to in the above by forming the disposable moist heating pad into a single package consisting of layers of material and including separate packages of the chemicals and solvent. The package includes a water absorbent material adjacent to the bottom layer that defines a continuous flat inner flexible surface that when applied is in contiguous contact with the skin of the patient being treated. The moist heating pad of this invention is disposable and utilizes a sealed chemical and solvent that produces an exothermic reaction when the frangible barrier separating the chemical from the solvent is broken. The face that is applied to the anatomy is formed from a non-woven fabric that is pervious to water and water vapor and allows the adjacent layer of a sponge-like material to absorb water. The volume of water contained in the sponge-like material is heated by the exothermic reaction upon the breaking of the barrier so as to apply a substantially uniform moist heat to the skin of the patient.
This invention is particularly efficacious for use in the medical procedure for obtaining a blood sample from an infant, particularly a premature baby. Typically such procedure includes obtaining the blood samples from the heel by the use of a well known lancet. As is well known, because of the minute diameters of the capillaries in this area of the anatomy, it is difficult or impossible to obtain samples of blood. The heel is preheated and this is typically done by a heated absorbent pad that is previously soaked in hot water. The absorbent pad is removed from the immersed hot water, either wrapped in a towel or the like or aloud to cool to a temperate temperature and then applied to the heel before the incision is made. The heat serves to dilate the capillary tubes and tends to bring them closer to the epidermis layer of the skin of the heel.
This heretofore known procedure in not only inefficient, it is also expensive. Typically, the absorbent material is designed for other procedures where the process of absorbing is the primary objective and the process of immersing the absorbent in hot water is time consuming, requires special attention so that the absorbent material is not applied when it is too hot to avoid scalding, and the heat dissipates relatively rapidly.
The disposable moist heating pad of this invention is ideally suited for this procedure inasmuch as it is less expensive than the absorbent pads that are typically used as was described in the immediately preceding paragraph, is less hostile to the patient, and distributes the heat more uniformly and longer with respect to time.